Transistor test socket



6 e 2 m Il- FIG.

INVENTOR Maurice H. Hansen 3,107,963 Patented Oct. 22, 1963 United States Patent Office TRANSISTOR TEST SOCKET Maurice H. Hansen, Garland, Tex., assigner to Atlantis Electronics Corporation, Garland, Tex., a corporation of Texas Filed oct. 1o, 1960, ser. No. 61,650 6 claims. (c1. 339-191) YThis invention relates generally to electrical sockets, and more particularly to improvements in transistor test sockets.

Presently available sub-miniature sockets of this class have met with `considerable dissatisfaction in the lield. During use they are apt to cause faulty circuits due to foreign inclusions accumulating in the vicinity of the contacts. Further inadequacies include rapid wear, which results in frequent and time consuming replacement. Such wear is partly the result of inadequate contact surface area between the transistor leads and the contact points, a feature which tends to cause variable resistance inthe circuit even when new.

It is therefore a primary object of this invention to provide a transistor test socket which overcomes the disadvantages outlined above to produce an efficient unit having readily replaceable contacts. o

It is a further object of this invention to providefa transistor test socket wherein one of the principal novel features comprises a reversible and removable spring o contact assemblyenabling rapid change of the contact surfaces of the socket.

It is a still further object of this invention to provide o a transistor test socket wherein the presently available point contact surface is replaced with a contact of increased surface area resulting in extremely low contact resistance.

It is yet a further object of this invention to provide a transistor test socket which contains spade type contact lugs permitting rapid change over of contacts without soldering.

Further objects and advantages of this invention will become apparent from the following more detailed description of a preferred embodiment thereof, taken in conjunction with the attached drawings wherein:

FIG. 1 is a cross sectional side elevation of the test socket shown with the spring contacts in position.

FIG. 2 is a cross sectional side elevation of the test socket taken along the line 2-2 of FIG. l.

FIG. 3 is a plan view of the complete socket which comprises my invention.

Similar reference characters indicate corresponding parts throughout the several views in the drawing.

Referring now to the drawings in detail, the numeral 5 represents the body of the socket which is designed for molding in one piece. The body consists of a rectangular casing 6 which has side walls 7 and end walls 8. The lower end of the two end walls 8 have normally extending ear portions 9 having central holes 10 formed parallel with the end walls for the purpose of securing the socket to the desired superstructure. The bottom end 11 is molded with three spaced openings 12 of rectangular cross section and having longer sides 13 disposed parallel to the end walls 8 and shorter sides 14 disposed parallel tothe side walls 7. The longer sides of the opening are provided with a semi-circular groove 15 disposed near the bottom of theopeningand parallel with the bottom end 11 of the socket body. The openings terminate inwardly of the body at 16 each extending to the same depth. The top 17 of the body 5 is recessed at 18 along the length of the opposing side walls 7, and is provided with tapered recesses 19 formed by four sided triangular based pyramids. Each recess is disposed in line with a spaced opening 12, and has sides formed at different vertical angles so as to terminate with an apex hole 20 communicating with the rectangular opening. The apex hole 20 locates centrally between opposed shorter sides 14 of the opening and toward onepend between the longer sides 13 of the opening. The holes 20 are adapted to receive the spaced prongs of a transistor which has not been shown on the drawings.

Received within each of the spaced rectangular openings 12 is a pair of springingly embracing contacts 21. The contact is formed from a strip of beryllium copper and comprises an end 22k from which projects two shaped contact arms 23. Each arm consists of a straight narrow portion 24 adapted to embrace the longer side 13 yof the d guide tongue 28. The inwardly bent portions 25 act to springingly engage the upper edges 27 of the two faces 26 and are shaped so that the gap indicated at 29 between the lower edges 30 is approximately .010 inch. In this configuration when parted by the prongs of a` transistor,ithe contact face will -be urged parallel with respect to each other and present flat contact surfacesto the introduced prongs. The end 22 of each contact 21 comes iiush with the bottom 11 of the socket body and is provided with a projecting spade type contact lug 31, secured thereto, and extending in the plane of the straight portion 24 of the contact arm. The terminating end of the lug 31 is bifurcated at 32 for simple securement to the test equipment without the use of solder. It will be noted by reference to FIG. 2, that the shape of the embracing contacts 21 is such that channels exist for the passage and self disposal of collected foreign matter that would otherwise tend to accumulate in the vicinity of the contact faces.

A study of the drawings will further indicate that each pair of contacts may be selectively reversed within their respective openings, such action enabling fresh unused surfaces of the contact faces 26 to be aligned with the prong holes 20.

The socket is to be molded from a material known as Teflon which` is characterized by extreme toughness, flexibility, and extremely low co-eflicient of friction. The material has further been chosen for its excellent electrical properties which include a power factor of less than 0.0003 over a frequency range of 60 cycles to 30,000 megacycles, and a dielectric strength range from 1,000 to 2,000 volts for high and low temperature applications. `The life of a socket formed of this material will be considerably longer than that of commerciallyV available sockets and only the removable spring contact points will require periodic inspection and reversal.

From the foregoing, it is believed that the construction, operation and advantages of this invention will be fully apparent. However, since numerous modifications will occur to those skilled in the art, it is not desired to limit the construction exactly to that shown and described, and accordingly, modifications and equivalents may be resorted to, falling within the scope of the appended claims.

I claim:

l. A test socket comprising, a body having parallel -openings formed' in the underside, said openings spaced from each other and terminating inwardly of the body, tapered recesses formed inthe top of the body and terminating in a hole communicating with the openings toward one side of the terminating end thereof, a pair of contacts removably received within the opening, said contacts having contact faces substantially lling the inwardly terminating end of the openings, said contacts being slideably removable from' the openings and replaceable therein after rotation through 180 to present fresh contact surfaces beneath the hole. V

2. A -test socket comprising, a body having spaced parallel openings of rectangular cross section formed yin the underside, said openings terminating linwardly of the body,'recesses having inwardly taperingl sides formed in the top of the body above each opening, said tapering sides forming an apex hole communicating :with each opening off centre with respect thereto, pairs of contacts received vin each opening having ilat portions embracing opposite sides of the opening, said pairs of contacts having embracing surfaces aligned-with the apex holes and extending across the terminating ends of the openings,

said contacts slideably removable outwardly of theopenl ings for rotation through-180 and replaceable therein to present fresh Contact surfaces beneath the apex holes.

3.,A test socket according to claim Z wherein bifurcated` contact lugs project'from the lower ends of .the pairs of contacts in alignment with one ofthe arm-s of the contacts.

4. A test socket comprising a body having spaced parallel openings of rectangular cross section formed in the underside, said openings Iterminating inwardly of the body, recesses having inwardly tapered sides formed in the top of the body above each opening, said tapered sides forming an apex hole communicating` with each Vopening off center with respect thereto, pairs of contacts received in each opening having Iiat portions embracing opposite sides of the yopening and grooves formed in opposing sides of the opening, said pairs of contacts consisting of strips of metal having a lower end from which project two spaced arms, said arms having outwardly protruding ribs releaseably engaging -within`saidgrooves, said arms eX- hole that communicates with one of the openings, a pair of cont-acts positioned within each of said openings, said contacts having contact faces substantially wider than said holes, and means releaseably holding'said contacts Within said openings, said contacts being positioned within said openings in alignment with said holes with the centers of said contact -faoes offset from the centers of said holes and slideably removable outwardly at the openings for 'rotation and replaceable therein" after rotation through 180 :to present fresh contact surfaces beneath the holes. 6. A -test socket as defined in claim 5 wherein said pair of contacts comprise a strip of metal having a lower end from which two spaced arms project, said arms extending upward and inwardly toward yeach other to form said lcontact faces springingly embracing each other -at the upper end of the faces, said faces further disposed such that said faces align with the surfaces of leads forcing said faces apart to formy surface contact therewith.

References Cited in the file of this patent FOREIGN PATENTS 369,019 Germany Feb. 13, 1923 875,059 Germany Q f Apr. 30, 1953 962,906 Germany e May 2, 1957 v811,085

Great Britain Apr. 2, 1959 

5. A TEST SOCKET COMPRISING A BODY HAVING AT LEAST TWO OPENINGS FORMED IN THE UNDER SIDE, SAID OPENINGS SPACED APART FROM EACH OTHER AND TERMINATING INWARDLY OF THE BODY, AT LEAST TWO TAPERED RECESSES FORMED IN THE TOP OF THE BODY, EACH OF SAID RECESSES TERMINATING IN A HOLE THAT COMMUNICATES WITH ONE OF THE OPENINGS, A PAIR OF CONTACTS POSITIONED WITHIN EACH OF SAID OPENINGS, SAID CONTACTS HAVING CONTACT FACES SUBSTANTIALLY WIDER THAN SAID HOLES, AND MEANS RELEASABLY HOLDING SAID CONTACTS WITHIN SAID OPENINGS, SAID CONTACTS BEING POSITIONED WITHIN SAID OPENINGS IN ALIGNMENT WITH SAID HOLES WITH THE CENTERS OF SAID CONTACTS FACES OFFSET FROM THE CENTERS OF SAID HOLES AND SLIDEABLY REMOVABLE OUTWARDLY AT THE OPENINGS FOR ROTATION AND REPLACEABLE THEREIN AFTER ROTATION THROUGH 180* TO PRESENT FRESH CONTACT SURFACES BENEATH THE HOLES. 